Diesel fuel contains approximately 12% more energy than petrol and diesel engines have a higher thermodynamic efficiency than petrol engines. The net result is that diesel engines are 20-30% more fuel efficient than petrol engines.
Diesel engines contribute to reduced CO2 emissions. However, the political debate has evolved from CO2 and climate change toward NOx and air quality. Several major Tier I suppliers to the automotive industry have presented solutions to reduce diesel NOx emissions below legislated levels. These solutions are generally based on combining established treatment technologies to sequentially reduce the NOx. These technologies can enable continued use of diesel engines in larger SUV, luxury vehicles and pick-ups, where the benefits are greatest, and where drivers seek the drivability, range and fuel economy offered by diesels. The cost of these technologies may be too high for lower cost vehicles, reducing the diesel take rate in small vehicles.
NOx commentary from the 2017 AGM presentation
Watch the NOx commentary from the 2017 AGM presentation of CEO Steve Dawson